In Long Term Evolution (LTE), which is a wireless communication standard of 3rd Generation Partnership Project (3GPP) or LTE-Advanced (LTE-A), which is an evolution of LTE, orthogonal frequency division multiple access (OFDMA), which is strongly robust to a frequency-selective channel and highly compatible with multiple input multiple output (MIMO) transmission, has been adopted as a transmission scheme in downlink (DL) (communication from a base station to a mobile station).
On the other hand, in uplink (UL) (communication from the mobile station to the base station), the cost and scale of a terminal (mobile station or mobile terminal) are important. However, multi-carrier transmission of orthogonal frequency division multiplexing (OFDM) or the like is not suited for UL transmission because a peak to average power ratio (PAPR) of a transmission signal is high and a power amplifier having a wide linear region is necessary. That is, single-carrier transmission having a low PAPR is desirable to maintain wide coverage in UL, and single-carrier frequency division multiple access (SC-FDMA) (also referred to as discrete Fourier transform spread OFDM (DFT-S-OFDM)) is adopted in UL of LTE.
In LTE-A, clustered DFT-S-OFDM is determined to be adopted in addition to SC-FDMA as an access scheme of UL so as to achieve greater system throughput than that of LTE. In clustered DFT-S-OFDM (hereinafter referred to as “clustered”), a frequency spectrum continuously arranged in SC-FDMA can be divided and non-continuously arranged. Because the non-continuous arrangement is acceptable, the improvement of frequency utilization efficiency by the active use of a frequency having a high gain that is non-continuously present or the improvement of availability of a system frequency by flexibility of frequency scheduling in the base station is expected.
However, the clustered scheme has a problem in that the PAPR is deteriorated as compared to SC-FDMA. Here, because a user near the base station can satisfy the quality of reception in the base station at low power, the linearity of an amplifier of the mobile terminal is not particularly problematic. Accordingly, a user close to the base station performs transmission using clustered DFT-S-OFDM and a user far from the base station performs transmission using SC-FDMA, so that it is possible to achieve high system throughput while coverage is maintained.
In addition, recently, even in MIMO in which transmission is performed using multiple antennas of a transceiver, single-user MIMO in which independent data is transmitted from multiple antennas provided in the mobile terminal at the same time and the same frequency is drawing attention as technology for improving a peak data rate of a user. In single-user MIMO, spatial filtering such as a minimum mean square error (MMSE), maximum likelihood detection (MLD), or the like is applied to a receiver, so that the separation of data is possible. In addition, it is possible to improve frequency utilization efficiency together using the MIMO transmission and the clustered scheme.
Incidentally, in LTE-A, frequency allocations of antennas of a transmitter are the same when MIMO is applied to the clustered scheme. However, a frequency having a high gain is different for every transmission antenna. Accordingly, as in FIG. 17, transmission having higher frequency utilization efficiency is possible by permitting different frequency allocation for every antenna as disclosed in Patent Document 1.